Compost - Natural Nutrient Cycling
Composting is an ideal way of turning household, garden and farm waste into a natural fertiliser, recycling waste you would otherwise have to get rid of. It is a very simple natural process whereby organic waste from plants or from animal manure can be broken down and returned to the soil. Composting can be as simple as creating a pile in the corner of the garden. Though for better management and results building some kind of enclosed area is advisable. The heap should not be completely sealed in as air must circulate through it. Old pallets are an ideal means of creating a simple put perfectly effective structure. For smaller gardens where space is limited or appearance is important a compost bin is probably the best way to go.
Over time the materials are naturally broken down and decompose. If the temperature is too low then this process will be mainly carried out by slow acting fungi. Although this cold heap will produce similar results in the end it is a much longer process that may take a couple of years. There is also the danger that seeds of weeds may not be killed off, nor diseases destroyed. For these reasons, as well as the issue of space, the faster acting hot heap is preferable.
In slightly warmer conditions the decomposition is driven by bacteria and worms. This activity naturally generates heat speeding up the overall process. In larger industrial scale heaps this can result in the heap catching fire, but it is not something to worry about if you have a small amount of material composting at home. In fact, you will want to encourage this warmth, locating your heap or bin in a warm and sheltered location. If you have an open heap you can cover it with a carpet to help keep it insulated.
The compost heap should be built up in thin layers of garden waste such as grass cuttings, hedge clippings, weeds and fallen leaves, and kitchen waste including raw vegetables and fruits well chopped up, kitchen roll and paper hand towels, tea leaves, tea bags and coffee grounds. Eggshells can be added but should be crushed and broken up. It is best to avoid using meat scraps, dairy products, bread or cooked food as this is likely to attract flies and rats. A small amount of ash from a wood or turf fire can be sprinkled on from time to time but it is best not to add too much. Thick sticks or wooden materials will not break down as they require slow fungal action.
A thin scattering of old compost amongst the layers helps introduce the essential bacteria for the process. These beneficial bacteria need air to work effectively. When beginning the heap, it is a good idea to have a base of material that allows air to circulate underneath, such as roots, stalks or straw. Shredded or crumpled paper or cardboard also lets air through, and they also create a good deal of heat as they break down. These aeration layers should be repeated at regular intervals as the heap rises. Using a variety of materials of different size and shape prevents packing down and ensures air gets to the various parts of the heap. As the decomposition progresses the activity of earthworms will naturally aerate it. However, if there are no air anaerobic bacteria, which do not need oxygen, take over the decomposition process, resulting in a stinking slimy mess. This can often be seen when grass cuttings have been left in a pile.
To help get the whole composting process going the heap needs an activator, a substance rich in nitrogen on which the bacteria feed. This could be part-finished compost, nettles, comfrey, seaweed, or animal manure. In fact, human urine is particularly effective. Adding layers of these materials helps to speed up the process whilst adding their own rich nutrients to the mix. It is an ideal way of using fresh animal manure, because the rich chemical content of manure can burn the roots of sensitive plants if it is added directly into the ground. Composting fresh animal manure helps to break it down, destroying harmful pathogens and unwanted seeds which it may contain.
To enhance the effect of your compost heap you may wish to add a light sprinkle of lime (peat or wood ash has the same effect and can also be used) to keep it “sweet”, preventing acidification and maintaining a good environment for worms and bacteria. The heap should be damp but not soaking wet. If it is in danger of drying out during the Summer some water can be added to moisten the heap. If it is getting too wet a cover can be used to keep the rain off and help keep heat in.
If the bin is full you may be able to take compost from the bottom so that the remaining contents fall down. If it’s not completely broken down you might consider getting a second bin. When one is full then empty it into the other. Turning ensures a better mix of materials, bacteria, worms and air. The more you turn a heap, the quicker it will rot down. A well-managed heap in summer can be ready in 3 months or less. Over the colder months or untended it can take more than 6 months. Heaps are generally dormant over the winter.
It is ready to use when the majority of individual ingredients are no longer identifiable, and it looks like rich dark soil. To get a more refined product you can use a large gauge garden sieve to sift out any large and lumpy bits which can go back into the next heap. The finished product should be light and crumbly, easy to store or ready for use. Compost should be dug-in as a soil improver. It provides a welcoming environment for friendly bacteria which fix nitrogen from the air further enriching the soil. Pure compost is too rich to sow seeds directly into it but it can be mixed about 1 part to 5 with potting compost for increased plant health.